Dear Lifehacker,
My wife just got her first iPhone, and I want to streamline everything we do: share our contact lists, calendars, task lists, grocery lists, etc. so we don't have two versions of everything floating around. How can I do this? I want as much of our daily info as collaborative as possible.

Sincerely,
Bringing a Luddite to the Light

Dear Bringing,
Being able to collaborate on stuff like this is one of the things that makes smartphones so great, and it's useful for more than spouses, too—roommates, family members, and other friends can benefit from this level of sharing too. We've shared a number of collaboration tools over the years, but here's a rundown of how to share your most important info on iOS and Android.

Contacts: Sharing your address book is one of the tougher options, but it isn't impossible. You can easily share your contacts by syncing them with iCloud, then just adding both iCloud or Google Contacts accounts to each phone. Of course, this requires that your spouse be logged into your iCloud or Google account, which isn't ideal for everyone. Soocial is an alternative, which syncs contacts between multiple Gmail accounts or Macs. It's free for 250 contacts and 3 sources, but costs $5 a month for more.

Calendars: Google Calendar makes it insanely easy to share calendars with multiple people. Just click the arrow next to any calendar, choose "Share this Calendar," and enter their email address. Be sure to give them permission to make changes, so they can add and tweak calendar events too.

Task Lists: A ton of different to-do apps offer collaborative lists; it just depends on which one you want to use. Check out our five best group task lists for a list of the best—most people recommend just using a shared Google document. You should be able to find something that suits your needs, though.

Grocery Lists: You could just use a shared document like with task lists, but there are some great collaborative shopping apps out there. We really like Grocery IQ, and it's pretty easy to use once you get it all set up. Plus it syncs with iOS, Android, and the web, so you can both access your list no matter where you are.

Photos: If you want to keep your photo libraries in sync, you have a few options. If you both use iPhones, than Apple's Shared Photo Streams are pretty cool: you basically create a Photo Stream and add your partner to it. After that, every photo you send to that stream will appear on their phone. Alternatively, if one or both of you is using Android phones, you can just use Dropbox. The Dropbox mobile app can automatically upload new photos you take, and you can just share that folder with your partner via the Dropbox web interface. Then you'll both have one, unified folder of all your photos.

Everything Else: These aren't the only things you can share, but the other options are too numerous to list here. Sharing travel arrangements is easy with TripIt, for example, and there are a number of good tools out there for sharing your budgets. And, for anything else, you can also just share an account with your spouse—with the same login and password, you can each access nearly any kind of service out there (as long as your comfortable with both of you having full access).

Hopefully this gets you started. You can find a collaborative version of just about any app if you do a little searching, but this should get you most of the important stuff shared between you. Good luck!